How did James prove that 'faith apart from works is dead'?

How James proved that 'faith apart from works is dead' (James 2:14-26).

1. James began by posing the question: what does it profit if a man says he has faith but has not works? Can that faith save him? The rhetorical question implies that such faith is worthless.
2. He gave a practical illustration. If a brother or sister is ill-clad and lacks daily food, and one of them says to them, "Go in peace, be warmed and filled," without giving them the things needed for the body, it profits nothing. Empty words without action do not help.
3. From this he drew the conclusion: so faith by itself, if it has no works, is dead.
4. He then answered an imagined objector who says, "You have faith and I have works." James challenged, "Show me your faith apart from your works, and I by my works will show you my faith." Faith is invisible unless it is expressed in deeds.
5. He pointed out that even the demons believe that God is one, and they shudder. Mere intellectual belief, which even demons possess, cannot save; it must be accompanied by obedience and action.
6. He gave the example of Abraham, the father of the faithful, who was justified by works when he offered his son Isaac upon the altar. His faith was active along with his works, and his faith was completed (perfected) by his works. Thus the Scripture, "Abraham believed God, and it was reckoned to him as righteousness," was fulfilled, and he was called the friend of God.
7. He concluded from this example that a man is justified by works and not by faith alone.
8. He gave a second example: Rahab the harlot was also justified by works when she received the messengers (spies) and sent them out by another way, protecting them at great risk.
9. Finally, he sealed the argument with a comparison: as the body apart from the spirit is dead, so faith apart from works is dead. Just as a lifeless body has no breath, so a faith that produces no good deeds has no life in it.

By these illustrations, examples and the closing analogy, James established that genuine, saving faith must always be accompanied by, and demonstrated through, good works.